I've also just run across the shape tag and I'm thinking it should be folded under either geometry or polygon based on questions.
I've been wondering about creating a general question in meta titled 'problem tags' or something similar. Maybe people could add them as answers and then answers deleted as they are addressed or declined? I know that sounds very similar to the synonym suggestion Q&A we had. I keep running into these little things that don't seem worth making a whole synonym proposal question for, but want to call attention to. Maybe I should just ignore them until I hit 10k.